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2004 Chevy Impala SS – There is a pulsing when pressing on the brakes. I’ve read that it could be a rotor issue, or an ABS issue. There are no warnings for ABS or traction control system that go on, so the most obvious thing to do is focus on the rotors first. (When you hear hoof beats, think horses, not zebras).
I will be inspecting the car tomorrow. What I need to find out is, if it is rotor runout, what’s the best strategy? Turn/replace rotors? I know that if the rotors are turned, there’s an issue of specs. I’m inclined to get new rotors BUT I read somewhere that if you don’t find out what’s causing rotor runout, then it will be back.
I don’t have a runout gauge, so since this is a friends car, I’m inclined to just replace the rotors and be done with it. But I’m afraid the problem will come back. New rotors were put on about 30K miles ago, by the dealer. So why is it having this issue?
What can I check to see what’s causing it, or am I obsessing? I’ve never had an issue with rotor runout on any vehicle I’ve owned, although I’ve replaced tons of scored rotors (hangs head). Could it be a caliper issue?
Any advice would be appreciated.
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[i]I don’t know if Eric has any info on this or not. This is the procedure that I had to do for warranty and every Impala had the issue.
[/i]It is very likely just warped rotors. Yes I said warped, it’s the easiest way to explain it. If it was/is an abs issue it would likely only be apparent when the ABS kicks in.
This is generally caused by heat. Your friend or whomever else drives that car probably rides the pedal more than they need to leading to warped rotors. They likely could be machined but by the time you pay, and then the time to remove them etc, your just making more work. Yes it might work out cheaper but what’s your time really worth to you? And then if the can’t be machined within spec they have to be replaced anyway. It’s a very common car so quality parts should be available without breaking the bank.
I would start with the front rotors, they take a majority of the abuse and in my experience cause most pulsation issues. Make sure you get OEM or better rotors, please. Buying cheap ones will only result in having messed up rotors again.
Before you install the new rotors, clean the mounting surface of the hub to remove any rust or dirt, a wire brush should work fine. Wash the rotors with soap and water first, then brake clean. Apply a small amount of anti-seize between the rotor and the hub to save swearing next time. Score up the pads a bit to get a good mating. This is also the perfect time to clean and lubricate the everything on the caliper.
Obviously if the pads are toast replace them too.
In my experience not only are new rotors crap these days but those cars seem to have pulsation issues. Heat is the biggest cause if the owner is an aggressive driver but if you live where they use salt and calcium chloride on the roads in winter they usually pitt and rust out. Rear rotors (if it has rear disc) are even worse than the front so make sure you inspect them also. Sometimes you can see a warped rotor by the appearance of the braking surface.
This is excellent advice. I have read that Impala’s have this issue more frequently than other vehicles. We have a 21 year old driving this car so a little education on brake riding seems to be in order. In addition, the vehicle is driven in the Chicago area, so salt and calcium are present.
I found the video fascinating, although, since this isn’t a warranty repair, it is more costly than simply replacing rotors.
I appreciate the tips on rotor replacement, such as making sure they’re clean and using anti-sieze on the hubs. These are things I do, but good to be reminded since I’m a backyard brake guy (smile).
That sets my concerns to rest – brake job with new rotors, and a little education on brake usage for the driver. I was concerned whether or not I had a primary issue causing this but it seems that this is not the case.
Thanks fellas.
I think what the video is illustrating that the hub flange’s are not made true and new rotors will wear out of specs after a period of time…repeat repair..
I had a runout issue on my last vehicle. I never did completely figure out what caused it, but I am very sure it was the wheel bearings. When I replaced the wheel bearings as well as the calipers, I had much smoother braking; though, the damage was already done from the warping. Spinning the rotor I could see it was actually warped, and it was not a cementite problem. I went through 8 rotors and 16 pads trying to figure it out – parts companies are very stubborn to take returns on brake parts I found…
Another thing to consider is whether the wheel is bent or not. A bent wheel can wobble and cause vibrations when braking. Both the wheel and rotor must be true for clean, smooth braking performance.
If you can get a ride and have the rotors turned at your local CarQuest, definitely do that. It’s only $15/rotor. If not, just get a pair of new rotors due to how cheap they are, get a piece of glass or a flat surface, and sand down the pads until you’ve removed all of the old glazed layer. This will basically give you new brakes, just with shorter pad life.
Wheel nut torque can also be an issue. As for determining the problem, I’ve actually done a video on it. The video, along with additional information on brakes can be found here.
http://www.ericthecarguy.com/faq/solving-brake-problems
Good luck and keep us posted on your progress.
Yes I agree on the car rotor resurfacing is the best.
One of the dealers I worked at sold Chevy’s and Ford’s. GM wanted you to do the Brake align method and Ford wanted you to do the on car resurfacing. Sometimes GM Techs would do brake complaints on Fords and to beat the clock time they would not do the on the car rotor resurfacing, only the Brake align method. Needless to say the customer didn’t know the difference and when the car went out of warranty usually the problem reoccurred.
[quote=”wysetech” post=95313]In my experience not only are new rotors crap these days but those cars seem to have pulsation issues. Heat is the biggest cause if the owner is an aggressive driver but if you live where they use salt and calcium chloride on the roads in winter they usually pitt and rust out. Rear rotors (if it has rear disc) are even worse than the front so make sure you inspect them also. Sometimes you can see a warped rotor by the appearance of the braking surface.[/quote]
Agreed! Most cars produced these days have really under sized brakes too if you compare them to cars from several years back that compare. I’m not talking high end sports coupes either. In Efforts to take weight out of the cars to make them slightly more fuel efficient the rotors are made smaller, thinner and cheaper to go along with the “tin” wheels and economy tires.
I agree with you on the new stuff they spray on the roads killing new cheap rotors too, or anything steel for that matter. On my own car the brakes as a whole are a year and a half old. Its even an upgraded bigger size brake at that. Nothing is pulsing or warped but by appearance they look 10 years old!
By experience the worst vehicle I’ve seen for brake warping is the Grand Cherokees and the Limited version. There is no way a vehicle of that size and weight should have brakes that small.
I went to a local parts store and asked to price new rotors. They had two different prices, I asked why one was $80 and one was $120 dollars and they told me it was the brand. I had them bring both out so I could look at them. They both would have fit my truck and would have worked. One was about a 1/2 in thinner than the other. The price difference was the amount of metal in the rotor. I tow a 8000 lb trailer, I bought the more expensive rotor. I don’t know how they sleep at night knowing most people wouldn’t know the difference.
Well, I finally replaced the rotors on this Impala and the pulsing stopped. I bought mid-grade rotors, so we’ll see how they hold up. The drivers side inboard surface of the old rotor was just “tore up”, most likely causing the pulsing. Interestingly enough, new rotors were put on a couple of years ago by a dealer repair shop, and this dealer is now out of business – go figure. The pads had plenty of life on them, but I replaced them anyway; cheap insurance.
In any event, I torqued everything to spec, including the lugs. We’ll see what happens over time, but for the time being, problem solved.
Thanks for all of the input.
Peace.
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